London rivals Arsenal and Chelsea have celebrated quarter-final victories to move within two matches of a possible Europa League derby final.
Arsenal added a 1-0 victory at Napoli - thanks to a superb first-half Alexandre Lacazette free kick - to their 2-0 first-leg home win for a 3-0 aggregate success over the Italians.
Chelsea scored three times in the opening 17 minutes but also survived a second-half scare as they beat Slavia Prague 4-3, with Pedro getting a brace and setting up the other two for a 5-3 aggregate win.
In the May 3 and May 10 semi-finals (New Zealand time), Arsenal face Valencia, who won a Spanish duel against Villarreal 5-1 on aggregate after a 2-0 second-leg win.
The 2013 champions Chelsea take on Eintracht Frankfurt, whose fairytale run continued when they overcame a 4-2 defeat in Lisbon to beat Benfica 2-0 at home after a controversial opening goal to advance on away goals.
The Baku final in Azerbaijan is on May 30.
In Naples, Arsenal flirted with early disaster when, and Arkadiusz Milik's goal was ruled just offside.
Aaron Ramsey then limped off, but the Gunners took the lead from Lacazette's 36th-minute free kick, wrong-footing Napoli keeper Alex Meret.
Napoli now needed four goals to advance, and Pierre-Emerick Aubameyang should have made it 2-0 in the second half, but it mattered little.
"All my teammates believe in me, so I'm happy to score tonight, and for them," Lacazette, in his second season in north London, said.
Chelsea, meanwhile, left it late in Prague but wasted no time at Stamford Bridge as Pedro chipped the opening goal in the fifth minute after completing a skilful attack with a one-two with Olivier Giroud.
Four minutes on, Pedro hit the post from point-blank range off Eden Hazard's cross but the ball cannoned back into the face of Simon Deli and into the net.
Pedro then set up Giroud to tap home for 3-0 in the 17th, his 10th goal of the campaign, and scored the side's fourth in the 27th minute, just two minutes after Slavia got on the scoreboard via captain Tomas Soucek.
However, Chelsea became sloppy, and two long-distance blasts from Petr Sevcik in the 51st and 55th saw Slavia save face.
"Maybe in an unconscious way we dropped the intensity down a little bit and even some technical mistakes, but this team never gives up," Giroud said.